Electronic mail is a popular way for people to send messages to one another. Common and accepted protocols such as Post Office Protocol (POP) and Simple Mail Transfer Protocol (SMTP) are used to handle electronic mail messages across a communications network. A typical electronic mail system includes one or more clients connected to a first server, and one or more other servers connected to that first server. Using protocols such as POP and SMTP, electronic mail messages are transferred between servers as well as between a client and its corresponding server.
An electronic mail message typically includes one or more header fields and a message body attached to those header fields. The header fields may include a “from” field identifying the sender, a “to” field identifying the recipient, a date sent field, and fields for other data. The message body may include ASCII text, text in hypertext markup language (HTML) form, data corresponding to a graphical icon representing an attachment, or other message data. One or more attachments may also form part of the electronic mail message, and may be attached to the end of the message after the message body. A mail server for handling electronic mail messages typically assigns each message received by that server a unique identifier. Electronic mail messages typically are transmitted from a mail server to a client program upon request by an authorized user, or automatically when received by the server.
If the user wishes to send a response to a particular electronic mail message, he or she typically can select a reply option offered by the mail client. The generation of the reply message is typically handled on the client side. The mail client copies the contents of the “from” field from the original message into the “to” field of the reply message, and may also copy the subject line and the body of the message. The mail client may also add a phrase or text element such as “RE:” or “REPLY:” to the beginning of the subject line of the reply message, and/or highlight the original text with carets or other symbols. If the original message was sent to a number of people, as is common in a business environment, the user may wish to reply to all of them. Typically, the user may do so by selecting a “reply to all” feature on the client side, in which case the contents of both the “from” field and the “to” field of the original message are copied into the “to” field of the reply message.
The popularity of electronic mail has resulted in a high volume of electronic mail messages. A given person routinely may receive thirty or more electronic mail messages in a single day. If that person is at a computer throughout the day, this volume of mail can be handled easily. However, if that person takes a vacation, or is out of the office, for several days or weeks, electronic mail messages can build up and form a large backlog. As the user works through these messages, he or she may reply to one of them, only to find that a later, as-yet-unnoticed message from the original sender or from another recipient of the original message made it unnecessary to reply. For example, a person in an accounting department at a company may send out an electronic mail message to other people in the accounting department, requesting information about a transaction. An electronic mail user who has been on vacation may reply to that message with that information, only to find that another member of the department has already provided that information, and sent it out to all of the recipients of the original message. Thus, when a user has a large backlog of electronic mail messages, he or she may waste time replying to messages when those replies are unnecessary.